This invention relates generally to exercise machines and more particularly to exercise machines with forced pronation or supination movement for the hands and arms.
Many athletes and non-athletes utilize weight lifting or weight training exercises to build strength and/or bulk, to prevent injury, or to improve overall condition and appearance. Typically, weight training exercises are performed with either exercise machines or free weights, i.e, barbells and weighted plates, dumbbells, etc. For various reasons, most exercise programs incorporate both machines and free weights in a variety of different exercise routines in order to maximize the effect of working the desired muscle groups.
Free weights offer a number of advantages over exercise machines. For instance, they are relatively inexpensive in comparison to exercise machines. Free weights are also more versatile because a variety of exercises can be performed with one set of weights, whereas most exercise machines are designed for only one exercise. Even though some exercise machines accommodate more than one exercise, the cost of these machines usually increases proportionately with the number of exercises. Use of dumbbells also enables both arms to be exercised independently. Finally, free weights are popular among many weight lifters because the lifting movements are not restricted to prescribed planes of motion or prescribed angles.
Nevertheless, there are also a number of inherent disadvantages associated with free weights. One such disadvantage relates to safety. Although most weight room instructors strongly advise against an individual working out alone, this cautionary measure is particularly important when the lifting of free weights is involved. This is due to commonly recognized dangers such as the possibility of dropping a weight on a body part, or becoming trapped beneath a bar, which could easily occur in exercises such as bench press, incline or squat. Additionally, through carelessness, loading and unloading of heavy weighted plates onto the ends of a bar sometimes results in an unbalanced bar that falls downward from its rack.
Another disadvantage associated with free weights relates to the fact that the weight resistance, or opposing force, that is exercised against is always directed vertically downward by gravity. Yet, the moment arm of the weight about the pivot point varies considerably throughout the full range of motion. This principle is explained in U.S. Pat. No. 3,998,454 with respect to a commonly performed exercise referred to as the dumbbell bicep curl. In short, during this exercise the applied moment arm about tie elbow varies according to the sine of the angle of the lower arm with respect to the vertically oriented upper arm. The moment arm is greatest when the angle is 90xc2x0 and it is lowest when the angle is 180xc2x0 and 0xc2x0.
If the resistance capabilities of the muscles of the human body matched this moment arm, the degree of difficulty experienced by the exerciser would be uniform, or balanced, throughout the entire range of motion. However, as reported in U.S. Pat. No. 3,998,454, the strength generated by the human muscles during this exercise is not in fact xe2x80x9cbalancedxe2x80x9d throughout the range of motion, and there are some xe2x80x9csticking pointsxe2x80x9d of increased difficulty. As a result, maximum benefits are not achieved when performing a bicep curl with a dumbbell.
The pullover machine disclosed in U.S. Pat. No. 3,998,454 utilizes an eccentric cam to vary weight resistance over the range of motion for the muscles utilized in a pullover maneuver. Over the years, for various muscle groups, a number of these cam and chain machines have been designed in an attempt to match a resistance variation through a range of motion with the natural strength curve for a particular muscle group associated with the range of motion. To the extent that these machines actually do succeed in approximating a resistance variation to an appropriate strength curve, an improvement over lifting of free weights probably has been achieved.
A number of exercise devices in the prior art allow the handles that the user grips to pivot freely while moving through. the desired range of motion for the prescribed exercise. However, a supination or pronation movement in the hands and forearms is desirable in conjunction with the standard range of motion for a specified exercise because additional muscle groups are exercised. Heretofore exercise devices have not typically included a forced pronation or supination movement of the hands and arms occurring as the hands and arms are moved through the desired exercise range of motion.
In accordance with the present invention, therein is disclosed an exercise device with forced pronation or supination movement of the hand and arms in conjunction with the standard range of motion for a specified exercise. The device comprises a conventional frame and a centrally mounted seat. The seat is bisected by a vertical midplane that extends through the middle of the frame. The device has two sides that are mirror images with respect to the vertical midplane.
Pivotally attached to the frame is a sub-frame including a pair of levers. A xe2x80x9cUxe2x80x9d shaped member attached between the levers provides structural support and requires the levers to pivot in tandem about a first axis of rotation A1.
Movably attached to the distal end of each lever is a double xe2x80x9cLxe2x80x9d shaped handle. The handle includes an elongated tubular grip section and a shorter cylindrical section attached 90xc2x0 to the grip. The cylindrical section passes through an opening in the distal end of the lever, thereby allowing pivotal movement of the grip about a second axis of rotation A2.
A second leg of the double xe2x80x9cLxe2x80x9d shaped handle is attached at a 90xc2x0 angle to the cylindrical section of the handle. A linkage rod is movably attached by means of a ball and socket connector to the distal end of the leg portion of the handle. The linkage rod is movably attached by means of a second ball and socket connector to the frame.
In operation, as force is applied by the exerciser to the handle, the lever of the sub-frame is pivoted forward about axis A1. As the lever pivots about axis A1, the handle is forced to pivot in a predetermined fixed relationship about axis A2. The hand and forearm of the exerciser undergoes a pronation or supination movement as the grip handle is pivoted about the axis A2 when the levers are pivoted about the axis A1. The hand and forearm also move down and in as the lever is pivoted.
In an alternate embodiment, a pair of miter gears are inserted in place of the linkage rod and ball and socket connectors. A stationary miter gear is located on a fixed axle and adjacent to the previously described lever. A hub is affixed to the proximal end of the lever oriented 90xc2x0 to the fixed axle. A rolling miter gear is mounted on the hub such that the rolling miter gear is oriented 90xc2x0 to the stationary miter gear. Attached to the rolling. miter gear is a bracket. As the rolling gear rotates, the bracket pivots about the hub in an axis A4, in a plane perpendicular to the plane of axis A1.
The distal end of the bracket is pivotally connected to the first end of the connector rod, allowing for pivotal movement of the bracket about an axis of rotation A5 that is parallel to, but displaced from, axis A4.
In the second embodiment, the handle includes an elongated tubular grip section and a shorter cylindrical section attached at a 90xc2x0 angle to the grip section, said cylindrical section passes through an opening in the distal end of the lever allowing for pivotal movement of the grip section about an axis of rotation A6.
Connected to the cylindrical section and perpendicular to the axis of the cylindrical section is a bracket. The distal end of the bracket is pivotally connected to the linkage rod. Pivotal movement of the linkage rod is allowed about axis A7 in a plane parallel to but displaced from the plane of pivotal movement of handle.
During operation of the second embodiment, as force is applied by the exerciser to the handle, the sub-frame is pivoted forward about axis A1. As the lever pivots about axis A1, the stationary gear forces the rolling gear to rotate. The bracket affixed to the rotating gear pivots about axis A4, perpendicular to axis A1, thereby forcing the linkage rod to pivot about axis A5. The linkage rod forces the bracket to rotate about axis A6, thereby pivoting the handle in a predetermined fixed relationship about axis A-6. The hands and forearms of the exerciser undergo a forced pronation or supination movement as the grip handle pivots about the axis A6 when the lever is pivoted about the axis A1.